This invention relates to a method for dyeing yarn and is more particularly concerned with a method for dyeing yarn with different colors or tones by means of application of dye colors to skein yarn packages.
Styling trends play an important role in the textile industry. Much emphasis has been placed of late on finishing a carpet in such a way that, although a single color remains the predominant base tone, a liveliness or an optically improved effect is obtained by dissolving the single color within a blend of yarns to achieve differing or variegated tones. In such carpets, the appearance of the surface does not have regularly recurring designs or patterns, nor does the carpet styling take on a geometrically defined outline. Rather, the carpet has a certain unified styling effect which, despite the randomness of color, is pleasant to the eye.
There are currently at least four commercial systems being used to space dye yarns used to fabricate multi-color carpets. These four systems may be divided into two basic classifications known as continuous systems and batch systems.
One of the two continuous systems used in the textile industry is the knit-de-knit space dyeing process which is generally described in U.S. Pat. No. 3,012,303, issued Dec. 12, 1961, to Ralph Whitaker. This process consists of six basic steps. The yarn is first knitted into a fabric after which a stripe or other pattern is printed on the knitted fabric. The color is set by steam color fixation of the knitted fabric which is then scoured to remove gums and excess dyes. After the knitted fabric is dried, the final step includes de-knitting of the knitted fabric to a cone of yarn.
The other of the continuous systems is generally known as warp printing. It also involves six basic steps including preparation of warp sheets (creeling) and thereafter application of a stripe or pattern which is printed on the warp sheet. The color is set by steam color fixation of the warp sheet which is then scoured to remove gums and excess dyes. After the warp sheet is dried, it is split and the yarns rewound onto cones.
Both types of the continuous systems suffer from similar disadvantages in that they require high levels of water consumption and expensive water treatment to remove pollutants. Costs of operation are high due to wasted energy in atmospheric steaming, continuous drying and high labor requirements.
The two batch systems in commercial use are injection dyeing and skein dyeing. Injection dyeing processes have been known for over a half of a century. Still, injection dyeing accounts for only a small portion of the textile yarn being dyed into multicolors. A typical process for injection dyeing is described in U.S. Pat. No. 1,726,984 to Louis Hasbrouck, dated Sept. 3, 1929. Another injecting dyeing process is disclosed in U.S. Pat. No. 3,120,422, dated Feb. 4, 1964. Both of these patents cover dyeing of one cone at a time with the use of hypodermic needles inserted into the cone of yarn to apply the dyes. As hereinbefore noted, injection dyeing processes have not found a great deal of commercial acceptance.
In the other of the batch systems used in the textile industry, the yarn is first unwound from its cones or bobbins to skeins which are loaded into the vat of a dye machine. The skeins are totally submerged in a dye bath and a base color is applied. The skeins are then partially raised out of the dye bath, and may further be rotated depending on the design of the machine and a second color is applied to the portion of the yarn submerged in the dye bath. This step is repeated for each additional color desired, after which the skeins are removed from the dye machine and put into a centrifugal extractor to remove the excess water. The skeins are then dried in an oven drier after which the skein dyed yarn is rewound on cones for further processing.
A typical apparatus for space dyeing of skeins by total submersion and application of a base color and thereafter selective withdrawal or raising of the skeins to apply additional colors to the partially immersed yarn was placed in commercial production in late 1971 by James H. Eakes and is described and illustrated in his application Ser. No. 480,026, filed June 17, 1974, now abandoned. Such apparatus for producing space dyed skeins of yarns is also described and illustrated in O'Mahoney, et al. U.S. Pat. Nos. 3,926,547 and 3,986,375.
It will be readily apparent to those skilled in the art that the apparatus for affecting space dyeing of yarn as described in the aforementioned Eakes application Ser. No. 480,026 and O'Mahoney U.S. Pat. Nos. 3,926,547 and 3,986,375 are but variations of the open dye vat apparatus of the type shown in Butterworth U.S. Pat. No. 1,911,305 and Helliwell U.S. Pat. No. 3,159,992 for dyeing skeins a single solid color. In the Butterworth patent, there is disclosed the basic open vat system which includes a skein carrier having laterally extending yarn support arms which may be rotated to insure subjection of all parts of the yarn skeins to treating dye liquid. The Helliwell patent employs a controlled distribution of dye liquor from a central source which produces a uniform lifting and "floating" of the skeins of yarn to provide a homogeneous dyeing. While the Butterworth and Helliwell patents are concerned with solid or single color dyeing, the Eakes and O'Mahoney, et al. methods and apparatus differ therefrom and achieve multicolor dyeing or space dyeing of yarns by use of a supercarrier or rack which is loaded with yarn and positioned above the internal skein carrier and dye tubes and selectively lifted and positioned between a fully lowered position in the dye bath and a plurality of raised positions.
Notwithstanding the fact that multicolor skein dyeing has experienced a certain degree of popularity due to the ability of yarn suppliers to provide materials which enable manufacturers of textile carpets to meet the demands for continuous changes in styling trends and ever-changing public tastes for color patterns which are out of the ordinary, little has been done to improve the efficiency of the batch operations of the type commercialized in 1971 by James H. Eakes and described in his aforementioned abandoned application Ser. No. 480,026 or that of U.S. Pat. Nos. 3,926,547 and 3,986,375 which suffer from many disadvantages.
For example, the supercarriers of such apparatus must be so constructed as to support the increased weight of yarns due to immersion. In each apparatus, a compromise is frequently reached by operation at less than full capacity of the machine to prevent bending of the cantilever yarn supporting tubes. Further, the apparatus is frequently subjected to hang-ups which interfere with production. To this end, the yarn after being immersed, expands or bulks out and because the yarn supported by the supercarrier must be withdrawn over the interior skein carrier and dye tubes, extraction is difficult. Another disadvantage is that the liquor ratio is not constant. That is, inasmuch as the entire vat is refilled each time a second dyestuff is added for each partial immersion of yarn, such a process also suffers from the disadvantage of high water consumption and high energy requirements needed to maintain operating temperatures of the liquid. Such batch operations require high liquor ratios which consume excessive quantities of dyestuffs and chemicals, thus increasing the cost of production. Accordingly, it is a principal object of the present invention to provide an improved method for space dyeing of yarns by the batch process.
It is another principal object of the present invention to provide an improved method for multicolor dyeing of skeins of yarn.
Another object of the present invention is to provide an improved method for space dyeing of textile yarns which is highly efficient and highly economical in operation.
Many of these disadvantages are either overcome or minimized by the process of the present invention wherein space dyeing of skeins of yarn is effected by adjusting the level of the liquid dye bath relative to the skeins while maintaining a constant liquor ratio and avoidance of the use of a supercarrier which must be selectively elevated. This enables an improved control of color reproduction from batch to batch.
Other features and advantages of the invention will become apparent to those skilled in the art upon a reading of the following description.